Plant recovery following prolonged drought in a shortgrass steppe

The recovery cycle of Bouteloua gracilis (H.B.K.) Griffiths after a 56-day drying cycle has been monitored to assess the effect of a prolonged drought upon the ability of different plant processes to respond to an increase in water availability. Leaf water potential before dawn and at noon recovered rapidly indicating that the previous drought had a minimal effect upon these variables. Leaf conductances during the first seven days of the cycle were considerably lower than the potential values estimated by a simple model, indicating that the prolonged drought had a profound effect on the behavior of stomata. Since leaf conductance represents the major control of photosynthesis during recovery cycles we suggested that the ecological significance of prolonged droughts and the after effects lies in their impact upon carbon assimilation.